This project is a coordinated activity of individual investigators acting as a research center. The greatest area of study is that of potency and toxicity of anesthetic agents. The studies of potency involve comparative pharmacologic effects of drugs, the effect of varying physical characteristics upon potency, the effect of changes in electrolytes and osmolality on anesthetic potency. We have specifically investigated the neuromuscular blocking agents and factors which alter neuromuscular pharmacology in man. Toxicity of drugs is being investigated in terms of the effects of prolonged exposure to small quantities of anesthetic agents especially as it related to possible carcinogenicity. We are studying the regulation of respiration in terms of the response to graded exercise, the hypoxic ventilation response related to blood desaturation and standardization of methods of determining and reporting carbon dioxide-oxygen responses. We have continued to study the effects of anesthetic agents and procedures on the welfare of the fetus and mother using the pregnant sheep as a model.